The present invention relates to an apparatus and method for feeding drums into a treatment chamber. The invention is described with reference to a plasma arc treatment chamber; however, any other type of treatment chamber may also be used.
In plasma arc treatment chambers a plasma torch transfers electrical energy through a stream of ionized gas so that the gas becomes an electrical conductor. With such a torch, temperatures of as much as 10,000.degree. C.-15,000.degree. C. can be attained. Generally speaking, a plasma torch disposal reactor raises the temperature of waste materials to such high levels that they chemically break down (pyrolysis). This breakdown can be enhanced by maintaining an atmosphere of appropriate gas in the incinerator. As a result, the residues are usually harmless gases and solids which can be suitably removed from the incinerator.
The commonly owned U.S. Pat. No. 4,912,296, for example, discloses an advantageous construction for a plasma torch incinerator. U.S. Pat. Nos. 4,770,109 and 5,136,137, both by the inventor of this application and also commonly owned, disclose and claim reactors for the incineration and melting of all types of materials, particularly hazardous waste, with which the invention of this application is particularly useful. The term hazardous waste as used herein refers to any type of toxic, nuclear, chemical, and/or biological waste. The disclosure of the commonly owned patents are incorporated herein by reference.
Other patents relating to the field of materials incineration and melting include U.S. Pat. Nos.:
______________________________________ 3,599,581 4,432,942 3,779,182 4,582,004 4,181,504 4,615,285 4,326,842 4,918,282 ______________________________________
and British Patent No. 1,170,548.
The reactor disclosed in the '137 patent uses a rotating, material-receiving drum or chamber into which the hot plasma of a plasma torch is directed. The inner surface profile of the rotating drum is appropriately shaped and constructed so that by varying the speed of rotation of the drum, materials placed into it are spread out over the inner surface of the drum in a relatively thin layer. The large surface area produced can be brought more quickly to the desired high temperatures generated by the plasma torch. The center of the drum forms a discharge opening through which incinerated and melted materials can be gravitationally withdrawn from the drum. The '137 patent discloses in detail how the material in the drum is melted and how the drum is constructed and operated for withdrawing the molten material.
U.S. Pat. No. 5,136,137 also discloses a known apparatus for introducing waste material into a treatment chamber. The treatment chamber has a material inlet 22 (FIG. 3A). A plunger valve 160 is coupled to the material inlet 22 at one end and to a screw feeder 161 at the other end. A thrasher 162 is attached to the inlet of the screw feeder 11. In use, a storage drum 163 containing hazardous waste is introduced into a container lock 164 which is coupled to a drum tipple 165. Waste material from the drum 163 is directed through lock 164, into thrasher 162, through screw feeder 161, past plunger valve 160 and into the reactor through pipe 22.
A problem with the method described in U.S. Pat. No. 5,136,137 is that the drum is opened outside of the treatment chamber thereby contaminating the area in which the drum is opened. The container lock 164 is exposed to the contents of the drum and must be decontaminated. A further problem with the conventional method is that the empty drum must be decontaminated and disposed of independently.